Juan-Andres Guerrero-Saade and Silas Cutler said in a blog post that they had given a name to this nation-state partnership: GossipGirl.
They claimed that malware named Flowershop, which was used in 2002, and malware known as Flame 2.0, found in 2016 were both connected to Stuxnet and Flame, the latter being used to spy on devices in the Middle East until it was outed in 2012 by Kaspersky Lab.
Stuxnet is said to have been developed by the NSA and Israel's Unit 8200 while Flame is suspected of having the same parentage.
The relationship between the malware created by the US-Israeli partnership.
Guerrero-Saade and Cutler used the YARA tool to scan years of code and look for similarities to these four malware samples. They said they had found two new matches that were similar to Stuxnet Flame, Duqu and Gauss.
One of these, called Flowershop, discovered by Kaspersky Lab in 2013 but not made public, had four communication modules in common with Stuxnet.
The second, which the two Chronicle researchers called Flame 2.0, was created in 2014 and uploaded to Google's VirusTotal database in 2016. But it was heavily encrypted and its functionality has yet to be ascertained.
The original Flame malware was thought to have been killed off by its Israeli creators in 2012, soon after its existence was made known. It was notable in that it used a cryptographic attack to impersonate a Windows Update server in a business and spread, as if legitimately signed by Microsoft.
"A better understanding of the institutions and incentives involved in cyber espionage further supports the view that threat actors don’t go away after exposure; our aggressors never truly vanish," Guerrero-Saade and Cutler wrote.
"They have an intelligence remit to fulfill and will go to great lengths in doing so. The defender community must be willing to match these efforts in order to insure the collective safety of users and organisations that lack the resources to defend themselves against the most formidable threat actors."